We have a right angle between the other two angles. The sum of all these angles must be 180. Then, we have:
[tex]9v+6+90+7v+4=180[/tex]
Then, adding like terms, we have:
[tex]9v+7v+6+90+4=180\Rightarrow16v+100=180\Rightarrow16v=180-100[/tex]
Then, we finally have:
[tex]16v=80\Rightarrow v=\frac{80}{16}\Rightarrow v=5[/tex]
Then, the values for v is 5.
